Centrifugal separator



"Feb, 16, 1943. c. E. BANNISTER 2,311,606

CENTRIFUGAIJ SELARATOR Filed Feb. 27, 1940 2 Sheets-Sheet 1 "sag l 64M@y I BY 9 1 g ATTORNEY Feb. 16, 1943. C E, BANNISTER 2,311,606

CENTRIFUGAL SEPARATOR Filed Feb. 27, 1940 2 sheets-sheer 2 ATTORNEYPatented Feb. 16, 1943 UNITED STATES PTENT OFFICE 8 Claims.

This invention relates to centrifugal separators and especially todevices adapted t Separate a finely divided and suspended solid from aliquid.

Its chief objects are to provide an improved apparatus for performingthe separating operation while the liquid is in transit, so to speak, asin the case of drilling fluid being drawn from the slush pit by a pumpin the drilling of deep wells such as oil Wells; to provide forseparating the materials while causing them to move upward, as in thecase of the drilling fluid just mentioned; to provide simplicity ofconstruction and of operation; and to provide economy of constructionand of operation.

Of the accompanying drawings:

Fig. 1 is a vertical axial section, with inner members shown inelevation, of an apparatus embodying my invention in its preferred form.

Fig. 2 is a section on line 2-2 of Fig. l.

Fig. 3 is a section on line 3-3 of Fig. 1.

Fig. 4 is a fragmentary elevation of the lower end portion of theapparatus.

Fig. 5 is a vertical middle section of a modification.

Referring to the drawings, I0 is a slush pit such as is employed in thedrilling of -oil wells, the liquid therein having its level at I l. Thesuction line of a pump is shown at I2, supported by means such as acable I3, and the terminal, vertical pipe section of the suction linehas mounted upon its lower end a stationary suction nozzle I4 formedwith intake holes I5, I5 and preferably of downwardly tapered form asshown and provided With a bottom end-closure I6 (Figs. 2 and 3).

At the upper end of the suction nozzle I4 its edge face, around the pipesection I2, provides a shoulder serving as the support for the lowerrace of a radial-and-thrust bearing Il which rotatably supports arotor-head member I8 which also is provided with a vertically extensiveradial bearing I9 interposed between it and the pipesection I2. Screwedupon a reduced upper end portion of the rotor-head member I8 is abeltpulley member adapted to be rapidly rotated l by a belt 2I forrotating the rotor-head I8 and a centrifugal separator device which isthreaded upon it at 22.

This separator device comprises a shell portion 23 which in spacedrelation surrounds the suci tion nozzle I4 and in the region of thelatter preferably is tapered downwardly at an angle of taper such thatthe flow capacity of the annular space between them is about the same atall eleannular space and entering the suction nozzle at variouselevations in the upward impelling of the fluid in the annular space.

In this annular space are two helico-spiral impeller vanes or ramps 24,24 which are in the relation of the threads of a double-threaded screwand which are secured throughout their length, at their outer margins,to the shell member 23 and at their inner margins have a preferablysealing fit against the stationary suction nozzle I4. Gaskets 25, 25 maybe set in grooves formed in the inner edge faces of the ramps, if foundnecessary or desirable under any particu lar set of speed and otherconditions, although ordinarily a little leakage at that position is notharmful.

At their lower ends the ramps 24 terminate at 24a, 24, at diametricallyopposite positions for balance of torque and of bearing load, and belowthe lowerrnost half-turn of each ramp the casing or shell member 23 iscut away as at 26 to permit liquid to be present in front of the mouthof the helico-spiral channels defined by the nozzle, the shell, and theramps, for a Pitot effect as an assistance to the centrifugal effect forcausing the ramps to lift the liquid to their upper ends and theredischarge it into the annular space defined by the shell, and the upperend portion of the shell is formed with a plurality of dischargeopenings 2l, 2 for the outflow from the shell of liquid heavily ladenwith the solid particles by reason of the centrifugal separationoccurring in the upward flow `of the liquid,

Preferably a conical apron 23, sloping downward outwardly, is mountedupon the shell member 23 just below the outlet openings 21, for throwingthe heavily laden liquid to such distance from the intake nozzle thatthe solids will largely settle out of it instead of being again drawninto the suction nozzle.

In the operation of the apparatus, the rotor comprising the shell 23 andthe ramps 24 being rapidly rotated in the direction of the arrow in Fig.3 and suction being applied to the pipe I2 and nozzle I4 by the pump,the sand laden water, for example, is caused to How upward between thevanes or ramps 24 both by the Pitot effect of the open mouths of theinter-vane spaces and by the centrifugal-pump effect resulting from thefact that the outlets 2'I are farther from the aXis of rotation than arethe said mouths of the inter-vane spaces.

It is desirable that the several dimensions of the parts of theapparatus be so correlated with vations excepting allowance for uidleaving the each other and with the speed of rotation that throughoutthe height of the vanes or ramps there will be a lag, which is to say arelative backward flow, of the liquid in relation to the ramps 24 andthe shell member 23, the liquid not attaining the full speed of therotor even at the tops of the Vanes or ramps, so that there will be awashing upward on the ramps, to the outlets 21, of the sand concentratedin the outer region of the inter-vane spaces.

Preferably the lower end portion of the suction nozzle I 4 isimperforate to a suicient height to assure centrifuging of the liquidbefore it reaches the elevation of any of the intake ports l5, so thatonly water made substantially free from sand by the centrifuging will bedrawn into the nozzle.

In order that the highest intake ports I5 of the nozzle may not beopened to the atmosphere by reason of centrifugal force of the watercausing it to bank up in the inter-vane spaces, thus leaving the nozzle,the outletports 27 can be made sumciently small to assure that all ofthe space between the nozzle and the shell will be at all times full ofwater, but, rather than to have such impedence of iiow, it is preferableto assure contact of the water with the nozzle throughout the region ofthe intake apertures primarily by so proportioning the parts that theflow capacity at all positions will be equal excepting an allowance forwater taken into the nozzle at positions lower than such position as maybe under consideration, so that the intervane spaces will be full ofwater throughout their cross-sectional areas and entirely to the tops ofthe vanes.

In the modication shown in Fig. 5, the casing 23a is non-rotating, beingxedly supported `from its upper end, where it is secured as by screws3G, 30 to a plate 'eil which is clamped between nuts 32, 32 screwed uponthe suction pipe lZa. The helico-spiral vanes 24a, Zta, for rotationwithin the stationary casing 23a, are secured to respective brackets orarms 33, preferably of stream-line cross-sectional form, by means suchas the screw 3.4., and these arms are secured at their upper ends, as bymeans of screws 35, 35, to a hubmember which is journaled upon thesuction pipe 62a by means or" radial bearings its and aradial-and-thrust bearing Via, and is formed at an intermediate portionwith an annular flange 31 which is grooved for the reception of adriving beltI Zia.

The casing 23a, in its upper portion, is formed with large holes 23h,23h, for access of water to the forwardly-facing mouths of theinter-vane spaces, the device being suspended so that at least the lowerportions of such holes are below the water level.

In this embodiment the hub-member 3S and with it the vanes 2lia aredriven in such direction that the vanes urge the lwater-and-sand mixturedownward while centrifuging it, and downward movement of sand,concentrated against and close to the outer casing 23a is somewhatretarded as to its rotary movement by frictional resistance withrelation to the casing, and this enhances the effect of the varies inurging it downward and expelling it at their lower ends, the principleinvolved being somewhat similar to that by which a sausage machine, -bycoaction of the screw and of the inner face of the cylinder of themachine, forces the sausage meat through the rotating apertured cutterdiscs. I do not wholly limit my claims to downward forcing of the sandin this way.

Fig. 5 shows the suction nozzle Ma and the casing 23EL as beingdownwardly flared, for centrifugal-pump effect, but this flare is lessimportant in this embodiment, with gravity helping to move the sanddownward, than it is in the upwardlyimpelling embodiment shown in Fig.l.

In this embodiment of Fig. 5, as well as in that of Fig. 1, theilow-space between the vanes 24a, 2lia preferably is of decreasingcross-section toward the delivery end of the device, to compensate -foriluid dra-wn into the suction nozzle at different positions along itslength, so that excessively low pressure of the fluid `against thesuction nozzle, as an incident of centrifugal force, is avoided.

The vanes dab may be secured at their inner margins to a very open,frusto-conical skeleton 33 to .prevent them from being excessivelysprung by centrifugal force or by theresistance of the fluid.

It will be manifest that in the operation of this embodiment shown inFig. 5 the intake water is drawn from the upper part of the body ofwater, where the sand or silt may have settled out previously, bygravity, to some extent, and that the discharge of water heavily ladenwith sand is nearer to the bottom of the pit, to which the dischargedsand can settle, and it is somewhat distributed by centrifugal force asit leases the lower end of the centrifuging device.

Various other modications are possible within the scope of the inventionas deiined by the appended claims.

I claim:

l. Centrifuging apparatus comprising a fluidintake nozzle leading to anoutlet for the lighter one of the substances separated, a non-rotatingcasing surrounding the same and having an outlet for the othersubstance, a member mounted between the two for rotation about thenozzle and having a face disposed in screw-thread relation to the axisof rotation and thus adapted in such rotation to impel axially of theassembly a fluid occupying the space between the nozzle and the casing,and means for so rotating said member.

2. Centrifuging apparatus comprising a nonrotating fluid-intake nozzleleading to an outlet for the lighter one of the substances separated, anon-rotating casing surrounding the same and having an outlet for theother substance, a member mounted between the two for rotation about thenozzle and having a face disposed in screwthread relation to the axis ofrotation and thus adapted in such rotation to impel axially of theassembly a fluid occupying the space ybetween the nozzle and the casing,and means for so rotating said mem-ber.

3. Centrifuging apparatus comprising a fluidintake nozzle leading to anoutlet for the lighter one of the substances separated, a casingsurrounding the same and having an outlet for the other substance, amember mounted between the two for rotation about the nozzle and havinga face having screw-thread relation to the axis of rotation and thusadapted in such rotation to impel axially of the assembly a iiuidoccupying the space between the nozzle and the casing, and means for sorotating said member, the said face being inclined in such direction asVto impel the fluid downward.

4. Centrifuging apparatus comprising a nonrotating suction pipe, afluid-intake nozzle mounted thereon, means surrounding said nozzle forcentrifuging a liquid passing thereinto, and means for supporting theassembly with the centrifuging means and the intake portion of thenozzle submerged in a surrounding body of liquid, said centrifugingmeans comprising a drum having an inlet opening and rotatable conveyingmeans communicating with said inlet opening and constructed and arrangedto receive liquid from said surrounding -body of liquid and convey italong said drum to said suction nozzle.

5. Centrifuging apparatus comprising a suction pipe, a fluid-intakenozzle mounted thereon and formed with radially-opening intakeapertures, means surrounding said nozzle for centrifuging a liquidpassing thereinto, and means for supporting the assembly with thecentrifuging means and the intake portion of the nozzle submerged in asurrounding body of liquid, the centrifuging means comprising structurewhich with the nozzle denes a helical flow .passage in communicationwith said apertures.

6. Centrifuging apparatus :comprising a nonrotating suction pipe, anon-rotating nozzle mounted thereon and formed with radiallyopeningintake apertures, means surrounding said nozzle for centrifuging aliquid passing thereinto, and means for supporting the assembly with thecentrifuging means and the intake portion of the nozzle submerged in asurrounding body of liquid, the centrifuging means comprising structurewhich with the nozzle defines a helical flow passage in communicationwith said apertures.

7. Centrifuging apparatus comprising a suction pipe, a fluid-intakenozzle mounted thereon and formed with radially-opening intakeapertures, means surrounding said nozzle for centrifuging a liquidpassing thereinto, and means for supporting the assembly with thecentrifuging means and the intake portion of the nozzle submerged in asurrounding body of liquid, the nozzle and the centrifuging means deninga helical IloW passage in communication with said apertures and having afluid receiving mouth Which is forwardly facing with relation to thedirection of rotation of the centrifuging means.

8. Centrifuging apparatus comprising a suction pipe, a fluid-intakenozzle mounted thereon and formed With radially-opening intakeapertures, means surrounding said nozzle for centriinging a liquidpassing thereinto, and means for supporting the assembly With thecentrifuging means and the intake portion of the nozzle submerged in asurrounding body of liquid, the nozzle and the centrifuging meansdefining two helical flow passages in communication 'with said aperturesand having respective diametrically opposite uid receiving mouths whichare forwardly facing with relation to the direction of rotation of thecentrifuging means.

CLYDE E. BANNISTER.

